Soluble oil



passed Jan. 25, 1944 UNITED STATES PATENT orricc SOLUBLE OIL John 0. Zimmer and George M. McNnlty,

Union,

N. J., assignors to Standard Oil Development Company, a corporation of Delaware No Drawing. Application September 13, 1940,

Serial No. 356,658

8 Claims.

contact. The use of these oil compositions ef- 10 fects many advantages, especially as regards lower power consumption, prolonging the life of the machinery and cutting tools employed and insuring better finish and quality of machine work. The emulsified compositions are preferred to unemulsified mineral oils in many cases because of the higher heat capacity and better viscosity characteristics of the emulsions. Some emulsions however foam badly due to the action of the emulsifying agents. The present invention is concerned with the preparation of emulsified compositions which do not foam to a harmful extent and more particularly it is concerned with the use of the agents in such compositions which suppress the foaming tendencies of emulsified mineral oil in water compositions without causing harmful effects on other properties of the emulsions.

The compositions of the present invention comprise a mineral oil of lubricating oil or lighter consistency, an emulsifying agent and a foam suppressing agent. Other constituents may be present such as dyes and antioxidants provided that such compounds do not impede or obscure the activities of the three main constituents previously mentioned. These additional materials are added to impart desirable features to the compositions'as a whole but are present solely as accessories and not as essential constituents from the point of view of the present invention. The order and method of adding the various ingredients may be varied to suit the convenience of the operator and the type of equipment for blending. 'In preparing compositions according to the invention, concentrated compositions are first prepared. The compositions are seldom utilized in this form but are prepared in this form for purposes of commercial distribution. These concentrated compositions can be readily dispersed in practically all proportions of either hard or soft water to prepare as required very stable emulsions. Examples of concentrated compositions are illustrated by the following:

Composition #1 Per cent Mineral paraffin base oil 81.98 Sodium mahogany sulfonate 12.00 Naphthenic acids 3.00 Sodium hydr 0.50 Ethyl alcnhnl 0,50 Water 2.00 Candelilla Wax 0.02

The sodium hydroxidein this composition is sufficient to neutralize the naphthenic acids present.

Composition #2 Per cent Mineral paraflln base oil 79.20 Sodium sulf 12.00 Rosin 4. 0 Sodium hydr xi 0.50 Ethyl alcohol 1.50 Water 2.00 Candelilla w x 0.20

derived as a distillate from a paraflinic or naphthenic type crude and a viscosity between and 200 seconds Saybolt at F. The oils may be refined by any of the conventional methods employing acid, alkali and/or clay or they may be extracted oils produced, for example, by solvent extraction of solvents such as phenol, sulfur dioxide, furfural and the like. Hydrogenated oils may also be employed as well as synthetic oils prepared for example by the condensation of olefins or the reaction of carbon oxides with hydrogen.

The emulsifying agents which are employed are of the type used in preparing miscible mineral oils, which form emulsions with addition of water, and include the water soluble alkali and alkaline earth metal soaps. In Composition #1,

a mixture of sodium mahogany sulfonate and naphthenic acids, together with sodium hydroxthe typesultable for use in cutting and grinding metal surfaces.

The emulsifying agents which are preferably employed are a mixture of naphthenate and sulme to neutralize the naphthenic acids and alcohol are added as the emulsifying agent and in Composition #2 sodium sulfonate, rosin, sodium hydroxide and alcohol are used as the emulsifying agent. The proportions in which these soaps are incorporated in the compositions depend on .the type of oil employed, its viscosity and the service in which the final composition is to be employed. The amounts in which these emulsifying agents are incorporated in the mineral oil water mixtures is determined preferably by actual test in the particular operation for which the emulsified compositions are primarily intended. In general, oils of relatively high viscosity require more soaps than those of low viscosity. In no case, however, does the amount of emulsifying agent employed exceed 40% by weight based on the amount of the mineral oil used in the finished soluble oil.

In preparing compositions according to the invention, naphthenate soaps are preferred to rosin soaps in the preparation of the emulsifying agent. In the concentrated composition in which form the soluble oils are usually made commercially available, naphthenate soaps form a more stable composition than that with rosin soaps. The use of naphthenate soaps obviates in this manner the need for employing stabilizing or coupling agents such as alcohol in appreciable quantities to maintain the actual emulsifying agents in dispersion in the oil and water. A comparison of Compositions #1 and #2 brings out this feature. Also, in compositions containing rosin soaps, there is a tendency for the constituents of the concentrate to separate on prolonged storage in open containers or if exposed to mild heating for a short period of time due to the loss of alcohol as the coupling agent. Furthermore, the naphthenates are preferable to rosin soaps in that when the concentrated compositions are agitated with water to form emulsions, the rosin soaps tend to precipitate out in hard water due to the formation of calcium or magnesium abietate. The naphthenates on the other hand form calcium or magnesium soaps which are more soluble in water than the rosin soaps. Thus, the maintenance or stability of emulsions is greater in the case of compositions containing the naphthenates than those containing the rosin soaps. As a cost item, the naphthenates are cheaper and more easily available than the rosin soaps.

An inherent disadvantage, however, of the use of naphthenates is the excessive foaming which occurs. Foaming is highly disadvantageous in the cold working of metals since the emulsified compositions are usually pumped on to the metal surfaces in large quantities and as a result, there is a tendency to aerate the compositions and develop as a result considerable amount of foam. Under these conditions, foaming over from the containing vessels or tanks often occurs and in the use of emulsions on the metal surfaces the,

cooling capacity is reduced considerably. The anti-foaming agents employed in the present invention are designed especially to combat the foaming tendencies of the naphthenate soaps. The anti-foaming agents of thi invention are, however, effective in combating the foaming tendencies of all mineral oil water emulsions of fonate soaps. The naphthenio acids employed are those derived from naphthenic type crudes, separation being effected when the crudes or any of their fractions are treated with alkali reagents and the resultant solutions acidified, preferably by means of mineral acid. The naphthenic acids preferably employed in this invention are derived -from the gas oil fractions. The sulfonate soaps are those prepared from the oil soluble petroleum sulfom'c acids of the Cu to Ca range. The mixture of these two types of soaps insures that the composite will have the desirable oil solubility characteristics of the sulfonate soaps and the desirable water solubility characteristics of the naphthenate soaps.

The emulsifying agent may be a sodium, potassium or onium base naphthenate or sulfonate.

Organic naphthenate soaps such as dior triethanol-amine naphthenate may be used. It is generally preferred to use a mixture of the naphthenates and sulfonates in the ratio of about 1 part of naphthenate to 4 parts of sulfonates. The amount in which the emulsifying agent is added to the mineral oil is usually between 5 and 40% by weight of the oil.

The anti-foaming agent consists of a small quantity of one or a mixture of waxes which contain a large percentage of unsaponifiable matter of relatively high molecular weight. These include the vegetable waxes, such as candelilla, carnauba, raphla, flax wax, cottonseed wax and palm wax. The term unsaponifiable matter is used here in accordance with the definition given by Holds-Mueller in Examination of Hydrocarbon Oils (1915) page 326, namely, Under the term unsaponifiable are included all those components of fats, oils and waxes which on boiling with potassium hydroxide are not changed into water-soluble substances. In the case of the waxes employed in the invention, the unsaponifiable materials consist of hydrocarbons and a1- cohols in which the hydrocarbon portions have more than 20 carbon atoms in the molecule. Candelilla wax, for example, contains a large proportion of normal dotriacontane (C32H66) and a small amount of oxylacetone (C30H5BO3) and some of the samples contain hentriacontane and myricyl alcohol. In general, waxes suitable for the purpose of the present invention are those which contain more than about 25% of unsaponifiable matter containing hydrocarbon portions having more than 20 carbon atoms in the molecule. These waxes are added to the concentrated soluble oil compositions in amounts between 0.001% and 0.5% by weight. The amount of wax added in any particular case should not be suflicient to cause separation of the wax from the oil at normal temperatures. It is preferable to heat the soluble oil composition to about the melting point of the wax and then to stir the mixture vigorously in order to incorporate the wax in the composition. Overheating of the oil should be avoided.

In order to demonstrate one of the favorable properties of the composition prepared according to the present invention, two compositions were prepared, namely, a. concentrated soluble oil composition containing a mixture of alkali metal sulfonate and naphthenate soaps in the ratio of 1 part of naphthenate to 4 parts of sulfonate as in 40 parts by weight of water; and a soluble oil of the same type but containing in addition 0.01%

of candelilla wax and emulsified with 40 parts of water. The two emulsions were tested using a Mixmaster agitator. The following results were obtained:

M immaster foaming test [700 R. P. M. for minutes, 500 cc. sample] This invention is not limited by any theories of the mechanism of the foaming or by any details which have been given merely for the purpose of illustration, but is limited only by the following claims in which it is intended to claim all the novelty inherent in the invention.

What is claimed is:

1. A composition of matter comprising a mineral oil containing a small amount of an emulsifying agent advantageous in the formation of oil in water emulsions and having the property of producing a substantial amount of foam under service conditions and a vegetable wax containing at least 25% unsaponifiable matter of relatively high molecular we ght inan amount to reduce substantially said foaming tendencies.

2. A composition of matter comprising a mineral oil containing a small amount of an emulsitying agent advantageous in the formation of oil in water emulsion, and having the property of producing a substantial amount of foam under service conditions and a quantity of a vegetable wax containing at least 25% of unsaponifiable matter having more than 20 carbon atoms in the molecule and inan amount sufficient to reduce substantially foam formation.

3. A composition of matter comprising a mineral oil containing a small amount of an emulsifying agent, advantageous in the formation of oil in water emulsions, and having the property of producing a substantial amount of foam under service conditions and between 0.001% and 0.5% by weight of a vegetable wax containing at least 25% of unsaponiflable matter having more than 20 carbon atoms in the molecule.

4. A composition of matter according to claim 2 in which the vegetable wax is candelilla.

. '5. A composition of matter comprising a mineral oil, a small percentage of an alkali metal naphthenate and between 0.001% and 0.5% by weight of candelilla wax.

6. A non-foaming emulsion comprising water, a mineral oil and an emulsifying agent selected from the class consisting of alkali metal naphthenates, alkali metal sulfonates and mixtures of alkali metal sulfonates and naphthenates and a vegetable wax containing at least 25% of unsaponifiable matter having at least 20 carbon atoms in the molecule and in an amount sumcient to reduce substantially foam formation.

7. A non-foaming emulsion according to claim 6, in which the vegetable wax is candelilla.

8. The method of reducing foaming of aqueous mineral oil emulsions of the type useful in the cold working of metals and which in service normally developed foam which comprises incorporating in such emulsions a small quantity of a vegetable wax containing at least 25% unsaponifiable matter of relatively high molecular weight.

JOHN C. ZIMMER. GEORGE M. McNULTY. 

